| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 15 |
55.6%
|
| 1999 | 1 |
3.7%
|
|
| 2000 | 2 |
7.4%
|
|
| 2005 | 1 |
3.7%
|
|
| 2007 | 2 |
7.4%
|
|
| 2009 | 1 |
3.7%
|
|
| 2012 | 1 |
3.7%
|
|
| 2019 | 1 |
3.7%
|
|
| 2021 | 1 |
3.7%
|
|
| 2023 | 2 |
7.4%
|
|
| Sysmiss | 84 |